The invention relates to a channel selection device used in a digital/analog broadcasting receiver and a digital/analog broadcasting receiver equipped with the same.
There has conventionally been available such a channel selection device used in digital/analog broadcasting receivers that permits the user to use input device to select a desired channel and decide whether this channel is of digital or analog broadcasting by referencing a digital/analog channel table listing the channels capable of viewing digital/analog broadcasts based on a digitally input channel number or using the channel UP/DOWN keys, thus causing a tuner thereof to receive a broadcasting signal of the desired channel (see, for example, Japanese Unexamined Patent Publication No. 11-164214).
Although, TV broadcasts are typically put on an air in analog origination, recently such digital broadcasts are originated and prevailing rapidly that are represented by a BS (Broadcasting Satellite) digital broadcast capable of improved high-picture-quality and multi-channel broadcasting and a CS (Communications Satellite) digital broadcast. The digital broadcasts in the North America, for example, are standardized by the ATSC (Advanced Television Systems Committee) to be originated through a physical channel different from analog broadcasting. In these broadcasts, many digital broadcasts are originated from the same or the same system of a broadcasting station as that for the conventional analog broadcasts, in which case to improve ease-to-use of the users accustomed to the conventional analog broadcasting channels, such a virtual channel that is assigned the same channel number as that for the conventional analog broadcasting is used in operation to enable channel selection and display.
Also, in digital broadcasting, each channel is assigned a carrier wave of a predetermined frequency band different from that of analog broadcasting. This channel is referred to as a main channel, which each contains one or a plurality of sub-channels for originating contents. The configuration of the sub-channels changes with a broadcasting time band, one of which is exemplified in FIG. 5 which shows a configuration of the sub-channels in a time band (8:00 PM to 12:00 PM) that has a main channel “4”.
In FIG. 5, in broadcasting, sub-channels of Nos. 0 to 4 are selected for 8:00 to 9:00 PM, sub-channels of Nos. 0 and 1 are selected for 9:00 to 10:00 PM, sub-channels of Nos. 0 to 4 are selected for 10:00 to 11:00 PM, and sub-channels of Nos. 0 to 3 are selected for 11:00 to 12:00 PM. The sub-channel of No. 0 (physical channel No. of 4-0) involves analog broadcasting according to the NTSC (National Television Systems Committee) Standard, while the sub-channels of Nos. 1 to 4 (virtual channels Nos. 4-1 through 4-4) involve digital broadcasting. Also, a TV program broadcast through the channel 4-0 is a prior art analog-broadcast one, an SD (Standard Definition) program broadcast through the channels 4-1 through 4-4 are digital broadcast standard-picture-quality one, and an HD (High Definition) program broadcast through the channel 4-1 is a high-picture-quality digital broadcast.
In digital broadcasting, the information (hereinafter referred to as channel information) of such fluctuating channel configuration as described above is originated together with a video signal etc. In the digital broadcasting receiver, therefore, the digital broadcasting signal can be received at a tuner and then decoded at a digital decoder to thereby analyze a VCT (Virtual Channel Table) contained in the resultant decoded signal, thus obtaining the channel information of the relevant broadcast.
There is such a prior art digital/analog broadcasting receiver's channel selection device that decodes and analyzes a broadcasting signal to obtain a VCT (Virtual Channel Table) containing virtual channel information based on PSIP (Program System Information Protocol) and hold a channel map storing this table, so that when the user changes or select a channel, based on this channel map, an EPG (Electric Program Guide) functioning as an interface is used to display a channel selection display to thereby operate the key (e.g., UP key/DOWN key) at the body's operation panel or remote-control panel, thus enabling him to change or select the channel. Although this configuration eliminates the troublesome necessity of inputting a channel number, if there is no sub-channel adjacent in a keyed-in direction in the same main channel, this main channel is changed.
For example, between 11:00 PM and 12:00 PM in FIG. 5, if the user press the DOWN key thinking that channel “4-4” is present when receiving a broadcast through channel “4-3”, the main channel (adjacent main channel, e.g. channel “5”) is also changed. The main channel is actually changed by changing the frequency received at the tuner, obtaining a VCT containing sub-channel information in the adjacent main channel, and, based on this information, extracting any sub-channel's broadcasting signal. The VCT, in particular, is originated as mixed with the broadcasting signal for each predetermined time lapse, so that it takes a considerable time to undergo these steps to thereby change the main channel. When the channel UP/DOWN keys are thus used to change the main channel, therefore, the channel selection step takes a long time, thus providing inconvenience. Also, users may have a favorite main channel (broadcasting station) and so want to change only sub-channels in this main channel, in which case also the channel UP/DOWN keys may be used mistakenly to thereby change the main channel against the user's will.